I couldn't do all the swapping I wanted as several sockets are weakening. Will order more.

To my ears there is a clear difference. Started with the reverse placement and immediately heard a richer, fuller sound. I stopped for the IsoTek process and an hour later, found pretty much the same - some, but not a large difference with burn-in.

Next was original placement and the sound was more defined but still had the same new warmth and fullness. In both positions dynamics sounded a bit more active and pronounced. The floor shaking low tones held their heft but gained more of a physical than audible nature - not a loss but a noticeable difference.

Replacing the standard caps only confirmed my impressions. They are still great sounding caps and I think they still offer the better cleanliness in the internals of placement across the stage. It will take some time but I think the depth of stage is also a tad deeper with the standard.

I'll do much more listening when I get some new sockets - but the total impact of these quick tests bring it back to the same old story. What a builder uses will be a subjective choice.

For me, the F series in the original placement get the nod. Acoustic guitar and small string group fans might indeed make a different selection.

In any event, no builder should feel they missed out by not getting their hands on the Standard BG caps. The F series are just fine and any differences can probably be mitigated by adjusting other caps and resistor in the build.

My experience has forced me to believe that there just isn't a "perfect" resistor or capacitor in several positions. C9 is now in that group. I think that's a positive set of options not necessarily a problem. I suspect if many builders go through the swapping process, some favorites will raise to the top. But the FEs and any other DIY amp offer - as the should - options to tailor to match the rest of ones system.

The guys with scopes and such will surely provide the tech specs for us to ponder

Never even considered anything other than the BG standard till last week. I plan to try several new things now that I've learned polarization is not an absolute requirement. Still cautious though, and will appreciate direction and advice from others.